Coil embolization as a safe and effective treatment for a large uterine artery aneurysm in a gravid female.

A 25-year-old G4P2 gravid female at 17-week gestation initially presented with “aching and throbbing” left lower quadrant pain. Her past medical history included a molar pregnancy, for which she underwent dilation and curettage 7 years ago. She had 2 subsequent pregnancies that she carried to term with normal vaginal delivery. Although she had been on an oral contraceptive, there was a lapse in treatment related to recent relocation. Patient denied any other medication or recreational drug use. Her physical exam was unremarkable except for left lower quadrant tenderness. Her beta-hCG was positive and within expected limits without concern for recurrent molar pregnancy or choriocarcinoma. She underwent pelvic ultrasound, which demonstrated a 6.1×4.3×4.1 cm left adnexal vascular structure with brisk turbulent color flow on Doppler ultrasound ( Fig. 1 ). For further characterization of this vascular lesion, she underwent MR imaging with ferumoxytol as the contrast agent. This showed a left UAA with a single arterial feeder supplying the saccular aneurysm on PC-VIPR sequences ( Fig. 2 ). She was discharged home from the ED with plan for outpatient management. The patient represented at 18-weeks of gestation with worsening pain and nausea without emesis or uterine bleeding. CT abdomen and pelvis with contrast showed increased size of the aneurysm sac now measuring up to 6.5×4.8×4.6 cm ( Fig. 2 ). Given the maternal risk of carrying the fetus to term, the multi-disciplinary team recommended initial endovascular management with embolization of uterine artery followed by termination of pregnancy. Fig. 1 (A-C) Ultrasound images of left adnexa showing an anechoic (1A), highly vascular structure with yin-yang appearance (1B) and turbulent internal flow (1C). Fig 1 – dummy alt text Fig. 2 (A-D) A large aneurysm in the left adnexa was identified on MRA (2A) and CTA (2B) at a bifurcation point without definite arteriovenous fistula, but apparent single arterial feeder on 4D Flow MRA (PC VIPR) arising of distal left uterine artery (2C-D). Fig 2 dummy alt text (A-C) Ultrasound images of left adnexa showing an anechoic (1A), highly vascular structure with yin-yang appearance (1B) and turbulent internal flow (1C). (A-D) A large aneurysm in the left adnexa was identified on MRA (2A) and CTA (2B) at a bifurcation point without definite arteriovenous fistula, but apparent single arterial feeder on 4D Flow MRA (PC VIPR) arising of distal left uterine artery (2C-D). A right common femoral artery access was obtained, followed by up-and-over catheterization of the left common and internal iliac arteries. The left uterine artery was selected with a 2.8 Fr microcatheter and a microwire; an arteriogram was performed. This showed a very tortuous left uterine artery supplying the large UAA arising off the ascending portion of the left uterine artery ( Fig. 3 ). Subsequently, distal left uterine artery was superselectively catheterized, just proximal to the aneurysm neck. Long segment coil embolization of left uterine artery was performed with multiple long detachable coils for dense mechanical occlusion and to minimize risk of recanalization through the coil pack. Repeat angiograms demonstrated near-stasis with minimal delayed opacification of the aneurysm sac. Further interrogation of the aneurysm sac with transabdominal gray-scale and color Doppler ultrasound was performed to determine embolization endpoint, which showed significantly decreased but persistent flow in the aneurysm sac ( Fig. 4 ). The coil pack was then further extended into the proximal uterine artery to maximize luminal occlusion. Completion angiogram showed no further opacification of the left uterine wall or the aneurysm ( Fig. 5 ). Completion ultrasound also confirmed absence of flow in the aneurysm sac ( Fig. 5 ). Related to right femoral artery vasospasm, hemostasis was achieved with manual compression. Fig. 3 (A-C) Digital subtraction angiography images from left uterine arteriogram via right femoral approach demonstrates a large tortuous left uterine artery on early phase (3A) with filling of a large UAA (3B) as well as left uterine wall without early venous filling to suggest an arteriovenous fistula. Fig 3 dummy alt text Fig. 4 Intraprocedural transabdominal color Doppler ultrasound of left adnexa showed partial thrombosis of the aneurysm sac with slower, but persistent inflow of aneurysm sac. Fig 4 – dummy alt text Fig. 5 (A-B) Post-embolization left uterine arteriogram (5A) showed filling of several uterine and lower cervical branches, but no opacification of the UAA or the left uterine fundus. This was confirmed with intra-procedural color Doppler ultrasound, which showed thrombosis of aneurysm sac and no further flow artifact. Fig 5 dummy alt text (A-C) Digital subtraction angiography images from left uterine arteriogram via right femoral approach demonstrates a large tortuous left uterine artery on early phase (3A) with filling of a large UAA (3B) as well as left uterine wall without early venous filling to suggest an arteriovenous fistula. Intraprocedural transabdominal color Doppler ultrasound of left adnexa showed partial thrombosis of the aneurysm sac with slower, but persistent inflow of aneurysm sac. (A-B) Post-embolization left uterine arteriogram (5A) showed filling of several uterine and lower cervical branches, but no opacification of the UAA or the left uterine fundus. This was confirmed with intra-procedural color Doppler ultrasound, which showed thrombosis of aneurysm sac and no further flow artifact. Repeat CTA on post-procedure day 1 showed no contrast enhancement in the aneurysm sac. On post-procedure day 2, patient underwent dilation and evacuation of the fetus with safety balloons positioned in the internal iliac arteries in case of a major blood loss. The operation went well with expected blood loss not requiring any transfusion or inflation of internal iliac balloon catheters. Patient recovered well thereafter, and 6-month repeat CT demonstrated persistent thrombosis of the UAA without interval recanalization ( Fig. 6 ). Fig. 6 Axial CT angiography image at 6-month follow-up demonstrated persistent thrombosis of the left UAA sac without contrast enhancement and with slight interval decrease in size. Fig 6 – dummy alt text Axial CT angiography image at 6-month follow-up demonstrated persistent thrombosis of the left UAA sac without contrast enhancement and with slight interval decrease in size.

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A written informed consent was obtained from the patient for the publication of this case report.

UAA is a rather uncommon entity, especially in a gravid female [ [5] , [6] , [7] ]. In a recent case report, UAE for a true aneurysm was performed safely in a gravid female with the pregnancy successfully carried to term [ 5 ]. Although radiation exposure is a risk of fluoroscopy-guided procedures, which is of particular concern during pregnancy, optimization of imaging parameters can help mitigate risk such as using collimation, low dose or low frame rate fluoroscopy or digital subtraction angiography [ 5 ]. In this case report with a multi-disciplinary decision to terminate the pregnancy for patient safety, and in accordance with the patient’s wishes, radiation exposure to the fetus was less relevant, but ALARA principles were still applied to minimize radiation exposure to this 27-year-old patient of child-bearing age. UAE is frequently performed with particles for the treatment of fibroids and adenomyosis. In the setting of uterine arteriovenous malformations, use of different embolic materials has been reported in the literature with a global success rate of 88.4-91% for symptom control and a major complication rate (eg, pulmonary embolism) of 1.6% [ 1 , 10 ]. Most UAEs for AVM treatment are performed with a combination of embolics (eg, glue, gelfoam, coils, etc.) [ 10 ]. Based on the angiographic images in our case, there was no evidence of early venous filling to suggest an arteriovenous fistula, so UAE with microparticles was considered during the procedure, especially to minimize the perioperative blood loss in the setting of planned dilation and evacuation. However, in order to prevent premature miscarriage or any sudden hemodynamic and hormonal changes prior to the planned surgery, the decision was made to proceed with UAE using microcoils. Another social consideration in using microcoils instead of particles was the possibility of a change in the patient’s care preference, such as a desire to complete the pregnancy to term despite the risks. During the UAE, multiple attempts were made to catheterize the 2 branch vessels more peripheral to the aneurysm sac to close any possible “back door” flow, but due to unfavorable angles and the size of the aneurysm, stable catheterization of these branches could not be achieved. To avoid prolonged radiation exposure, the UAE was instead performed with appropriately sized microcoils by closing the “front door” as close to the aneurysm sac as possible. The aneurysm sac itself, however, was not embolized to prevent any inadvertent rupture. It is important to highlight the use of intra-procedural ultrasound in this case. At the mid-embolization point after deploying a long coil pack to the level of horizontal segment of the uterine artery, an angiogram was performed, which showed very subtle and delayed filling of the aneurysm sac despite the use of DSA imaging. This subtle delayed filling could potentially have been missed, but intra-procedural grayscale and color Doppler ultrasound demonstrated partial thrombosis of the aneurysm sac with slow, but persistent inflow. This invaluable ultrasound data guided additional treatment, and the coil pack was further extended to cover the horizontal segment of the uterine artery until complete stasis was achieved both on DSA and intra-procedural ultrasound. These intra-procedural ultrasound images also allowed us to rule out any “back door” or collateral supply to the aneurysm, corroborating the MRA findings of a single feeder to the aneurysm from the left uterine artery. If persistent filling of the aneurysm was seen on ultrasound, further angiographic investigation such as an aortogram would be warranted to search for any variant supply to the left UAA. Even though the aneurysm did not opacify on post-procedure day 1, the multidisciplinary team was still concerned for the bleeding risk during the dilation and evacuation. Therefore, the interventional radiology team was asked to place internal iliac artery balloon catheters to be inflated in case of any major blood loss. Ultimately, the patient underwent an uncomplicated dilation and evacuation without significant blood loss or inflation of internal iliac artery balloon catheters, which further supports adequate stasis after UAE with microcoils only. Furthermore, CTA obtained at 6-month follow-up also demonstrated persistent thrombosis of the aneurysm sac with mild interval decrease in size. In brief, this case demonstrates immediate and short-term safety and efficacy of uterine artery embolization with microcoils for treatment a UAA.

Management of a rare entity such as UAA can be challenging given the limited available data in the literature. Treatment of other more common pathologies such as uterine AVM may not be readily applied to the treatment of UAA, particularly in a gravid patient. This case report supports that coil embolization of a UAA in a gravid female is a safe and effective treatment and can help minimize peri-operative blood loss during dilation and curettage or evacuation.

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Uterine arteriovenous malformations (AVMs), fistulas, or pseudoaneurysms can be seen in the post-traumatic, post-surgical, or peripartum settings [ [1] , [2] , [3] , [4] ]. Uterine artery aneurysm (UAA), on the other hand, remain a rare entity with limited data in the literature, comprised of case reports [ [5] , [6] , [7] ]. UAA can be asymptomatic or present with abdominal pain or metrorrhagia, reported even during pregnancy [ 5 , 7 ]. The initial diagnosis of UAA in a gravid female is usually made using transvaginal or transabdominal ultrasound, which can be further evaluated and confirmed with magnetic resonance imaging [ 8 ]. There is no standard of treatment for UAA, and a multi-disciplinary decision should be made with patients’ clinical status and decisions considered. Although not specific to UAAs, treatment of visceral artery aneurysms is highly recommended during pregnancy regardless of their size, owing to significant hormonal and hemodynamic changes related to pregnancy [ 9 ]. Minimally invasive endovascular treatments are the first-line management of many visceral aneurysms or pseudoaneurysm if technically feasible [ 9 ]. Uterine artery embolization (UAE) is a frequently utilized treatment method for a multitude of uterine pathologies including acquired uterine AVMs, or more recently referred as enhanced myometrial vascularity [ 1 ]. Here, we present a case report of a large UAA in a gravid female which was treated with technically and clinically successful UAE with coils.